Marked chromosomes associations in catarrhine monkeys, with a note on chromosome associations in other primate groups

In metaphase figures, obtained from cultures of whole blood, associations of the marked chromosomes were found in species of the following genera: Macaca, Cercocebus, Cercopithecus and Symphalangus. The different types of these associations are discussed. A note is given on chromosome associations found in some species of Prosimii and Platyrrhinae

Effects of oviposition in a non-host species on foraging behaviour of the parasitoid Cotesia glomerata

Parasitoids lay their eggs in or on a host, usually another insect. During foraging, parasitoids can encounter insects that differ in terms of host suitability and quality. At one extreme end of this spectrum are non-hosts that are unsuitable for offspring development.Non-hosts are generally ignored but parasitization does occur and occasionally also results in egg deposition. Here, the authors investigate how oviposition in a non-host influences subsequent foraging behaviour of a parasitoid and whether this is mediated by learning. The study system consists of the endoparasitoid Cotesia glomerata and the presumed non-host caterpillar Mamestra brassicae.In the presence of Pieris brassicae hosts and/or their traces (frass), C. glomerata inserted its ovipositor into M. brassicae caterpillars. Eggs were deposited, but all eggs disappeared within 96 h, confirming the non-host status of M. brassicae. In contrast to the expectation, there was no memory retention after oviposition in a non-host and parasitoids did not alter their behaviour with respect to non-host contacts and ovipositions. Instead, C. glomerata became more motivated to forage on a non-host infested leaf.The authors propose that egg deposition in non-hosts by C. glomerata might be due to their high egg load, which is thought to make parasitoids less selective on host quality, especially when they have few reproductive opportunities. In such cases, fitness costs to individual females are low. Egg deposition in non-hosts might ultimately lead to host range expansion if parasitoids overcome the defence response of non-hosts over evolutionary time

Memory extinction and spontaneous recovery shaping parasitoid foraging behavior

Animals can alter their foraging behavior through associative learning, where an encounter with an essential resource (e.g., food or a reproductive opportunity) is associated with nearby environmental cues (e.g., volatiles). This can subsequently improve the animal’s foraging efficiency. However, when these associated cues are encountered again, the anticipated resource is not always present. Such an unrewarding experience, also called a memory-extinction experience, can change an animal’s response to the associated cues. Although some studies are available on the mechanisms of this process, they rarely focus on cues and rewards that are relevant in an animal’s natural habitat. In this study, we tested the effect of different types of ecologically relevant memory-extinction experiences on the conditioned plant volatile preferences of the parasitic wasp Cotesia glomerata that uses these cues to locate its caterpillar hosts. These extinction experiences consisted of contact with only host traces (frass and silk), contact with nonhost traces, or oviposition in a nonhost near host traces, on the conditioned plant species. Our results show that the lack of oviposition, after contacting host traces, led to the temporary alteration of the conditioned plant volatile preference in C. glomerata, but this effect was plant species-specific. These results provide novel insights into how ecologically relevant memory-extinction experiences can fine-tune an animal’s foraging behavior. This fine-tuning of learned behavior can be beneficial when the lack of finding a resource accurately predicts current, but not future foraging opportunities. Such continuous reevaluation of obtained information helps animals to prevent maladaptive foraging behavior

A note on the karyotypes and chromosome associations of the Hylobatidae, with special reference to Hylobates (Nomascus) concolor

The somatic chromosomes, obtained from short term leukocyte cultures, were studied of four species of the Hylobatidae: Hylobates lar, H. agilis, H. (Nomascus) concolor and Symphalangus syndactylus. In accordance with earlier observations by others, the diploid chromosome numbers were found to be 44 in both Hylobates lar and H. agilis, 52 in H. concolor and 50 in Symphalangus syndactylus. The chromosome associations observed in metaphase spreads are clearly different in the three types of chromosome complements. In Hylobates lar and H. agilis associations are found between both members of the marked chromosome pair. In Symphalangus syndactylus the only two acrocentric elements of the karyo-type, which are of medium size, associate frequently. In H. concolor finally, the members of three pairs of small acrocentrics are involved in chromosome associations. G-banding patterns (obtained by trypsin treatment) showed that in a male individual of this species also the small acrocentric Y chromosome sometimes participates in these associations. The evolutionary aspects of these observations are briefly discussed

Complementary sex determination in the parasitoid wasp Cotesia vestalis (C. plutellae)

In the Hymenoptera, single locus complementary sex determination (sl-CSD) describes a system where males develop either from unfertilized haploid eggs or from fertilized diploid eggs that are homozygous at a single polymorphic sex locus. Diploid males are often inviable or sterile, and are produced more frequently under inbreeding. Within families where sl-CSD has been demonstrated, we predict that sl-CSD should be more likely in species with solitary development than in species where siblings develop gregariously (and likely inbreed). We examine this prediction in the parasitoid wasp genus Cotesia, which contains both solitary and gregarious species. Previous studies have shown that sl-CSD is absent in two gregarious species of Cotesia, but present in one gregarious species. Here, we demonstrate CSD in the solitary Cotesia vestalis, using microsatellite markers. Diploid sons are produced by inbred, but not outbred, females. However, frequencies of diploid males were lower than expected under sl-CSD, suggesting that CSD in C. vestalis involves more than one locu

Multi-camera field monitoring reveals costs of learning for parasitoid foraging behaviour

1. Dynamic conditions in nature have led to the evolution of behavioural traits that allow animals to use information on local circumstances and adjust their behaviour accordingly, for example through learning. Although learning can improve foraging efficiency, the learned information can become unreliable as the environment continues to change. This could lead to potential fitness costs when memories holding such unreliable information persist. Indeed, persistent unreliable memory was found to reduce the foraging efficiency of the parasitoid Cotesia glomerata under laboratory conditions. 2. Here, we evaluated the effect of such persistent unreliable memory on the foraging behaviour of C. glomerata in the field. This is a critical step in studies of foraging theory, since animal behaviour evolved under the complex conditions present in nature. 3. Existing methods provide little detail on how parasitoids interact with their environment in the field, therefore we developed a novel multi-camera system that allowed us to trace parasitoid foraging behaviour in detail. With this multi-camera system, we studied how persistent unreliable memory affected the foraging behaviour of C. glomerata when these memories led parasitoids to plants infested with non-host caterpillars in a semi-field set-up. 4. Our results demonstrate that persistent unreliable memory can lead to maladaptive foraging behaviour in C. glomerata under field conditions and increased the likelihood of oviposition in the non-host caterpillar Mamestra brassica. Furthermore, these time- and egg-related costs can be context dependent, since they rely on the plant species used. 5. These results provide us with new insight on how animals use previously obtained information in naturally complex and dynamic foraging situations and confirm that costs and benefits of learning depend on the environment animals forage in. Although behavioural studies of small animals in natural habitats remain challenging, novel methods such as our multi-camera system contribute to understanding the nuances of animal foraging behaviour

Discussion on Emergencies in General Practice

In the Hymenoptera, males develop as haploids from unfertilized eggs and females develop as diploids from fertilized eggs. In species with complementary sex determination (CSD), however, diploid males develop from zygotes that are homozygous at a highly polymorphic sex locus or loci. We investigated mating behavior and reproduction of diploid males of the parasitoid wasp Cotesia vestalis (C. plutellae), for which we recently demonstrated CSD. We show that the behavior of diploid males of C. vestalis is similar to that of haploid males, when measured as the proportion of males that display wing fanning, and the proportion of males that mount a female. Approximately 29% of diploid males sired daughters, showing their ability to produce viable sperm that can fertilize eggs. Females mated to diploid males produced all-male offspring more frequently (71%) than females mated to haploid males (27%). Daughter-producing females that had mated to diploid males produced more male-biased sex ratios than females mated to haploid males. All daughters of diploid males were triploid and sterile. Three triploid sons were also found among the offspring of diploid males. It has been suggested that this scenario, that is, diploid males mating with females and constraining them to the production of haploid sons, has a large negative impact on population growth rate and secondary sex ratio. Selection for adaptations to reduce diploid male production in natural populations is therefore likely to be strong. We discuss different scenarios that may reduce the sex determination load in C. vestalis

DNA nuclear content in the cytotaxonomy of Galago senegalensis and Galago crassicaudatus

The DNA nuclear content in lymphocytes of peripheral blood from Galago senegalensis (2 males and 2 females), Galago crassicaudatus (3 males and 2 females) and Perodicticus potto (2 males) was measured by means of the Deeley integrating microdensitometer. The mean of the DNA content does not differ significantly between Galago senegalensis and Galago crassicaudatus specimens, nor does it between the two Galago and Perodicticus potto. This finding lead us to exclude that the difference in the chromosome number between Galago senegalensis (2n = 38) and Galago crassicaudatus (2n = 62) is the result of endoreduplication. In addition, these preliminary findings seems to lend further support to the assumption of a stronger affinity of the Galagidae with the Lorisidae rather than with the Lemuridae

Complementary sex determination in the parasitoid wasp Cotesia vestalis (C. plutellae)

In the Hymenoptera, single locus complementary sex determination (sl-CSD) describes a system where males develop either from unfertilized haploid eggs or from fertilized diploid eggs that are homozygous at a single polymorphic sex locus. Diploid males are often inviable or sterile, and are produced more frequently under inbreeding. Within families where sl-CSD has been demonstrated, we predict that sl-CSD should be more likely in species with solitary development than in species where siblings develop gregariously (and likely inbreed). We examine this prediction in the parasitoid wasp genus Cotesia, which contains both solitary and gregarious species. Previous studies have shown that sl-CSD is absent in two gregarious species of Cotesia, but present in one gregarious species. Here, we demonstrate CSD in the solitary Cotesia vestalis, using microsatellite markers. Diploid sons are produced by inbred, but not outbred, females. However, frequencies of diploid males were lower than expected under sl-CSD, suggesting that CSD in C. vestalis involves more than one locus. [KEYWORDS: developmental mortality ; diamondback moth ; diploid males ; inbreeding ; mating system ; sex ratio